Elevation of endothelin biosynthesis in human endothelial cells with mycoplasma infection

The effects of mycoplasma infection on the biosynthesis of endothelin-1 (ET-1) in cultured human vascular endothelial cell lines were examined to understand regulatory mechanisms of ET-1 biosynthesis and causes of angiopathy due to mycoplasma infection. The growth of normal endothelial cells from the umbilical cord vein and of an immortal endothelial cell line transfected with prepro ET-1 cDNA was decreased, while the secretion of ET-1 into the culture medium was enhanced by mycoplasma infection. However, the rate of ET-1 production in these cell cultures was much higher at the growing phase than at the stationary phase. Immunocytochemical studies with anti-ET-1 antibody and an autoradiographic examination of the labeled nuclei with 3H-TdR revealed that mycoplasma infection induced an elevation of ET-1 production in both S and non-S phase cells. The expression of prepro ET-1 mRNA as examined by in situ hybridization and by RNase protection assay was not altered by mycoplasma infection. Thus, the biosynthesis of ET-1 in vascular endothelial cells may be regulated at the posttranscriptional level.